Holding arms of the kind initially specified have long been known from the prior art and are specifically used in surgery to relieve an operator of static holding work. Such a holding arm is used to hold a mechatronic assistance system and/or a surgical instrument, for example a manipulator, an endoscope, a surgical clamp or the like. The holding arms initially specified have proved their usefulness for holding endoscopes, in particular. In endoscopic surgery, an operator generally operates an instrument with both hands, while an assistant holds the endoscope in order to make the operating area visible on a screen. Holding the endoscope over a protracted period is very tiring. Holding arms are increasingly used for that reason.
Such a holding arm is known from DE 195 26 915 B4, for example. The holding device for medical purposes disclosed therein has a connection member and a holder for surgical tools, as well as an arm arranged between the holder and the connection member. The arm is connected to the holder and to the connection member, or to an adjacent arm via a joint, and can be coupled to a pneumatically operable device for selectively locking and releasing the joints, wherein the device locks the joints by the action of a mechanical spring which exerts a braking force on the joint, and wherein the device can be pneumatically switched to a joint-releasing mode against the force of that spring. An actuator by means of which a valve can be opened is disposed on the holder at the proximal end of the arm, so that the separate joints of the arm can be adjusted. When the actuator is released, the valve is closed again, thus locking the joints.
A similar holding arm is disclosed in EP 1 958 587 B1. The holding disclosed therein likewise has a plurality of joints, and a touch-sensitive sensor for actuating the joints is provided. The sensor is disposed on the holding arm adjacent to the medical instrument, so that the operator comes into contact with the touch-sensitive sensor on gripping the medical instrument, as a result of which the joints of the holding arm are released.
The holding arm disclosed in DE 195 26 915 B4 and also the one disclosed in EP 1 958 587 B1 is used primarily as a kind of exoskeleton for the operator, so that the operator can rest on the holding arm during the operation and can release all the joints on gripping the medical instrument or when operating the actuator, so that the pose of the holding arm can be altered.
Another holding arm, adapted to hold an endoscope, is known from DE 10 2004 050 714 A1. The arm has a plurality of joints which can be closed pneumatically. The holding arm is connected to a foot-switch valve. When the foot-switch valve is operated, compressed air enters all the joints, thus releasing them.
Another such holding arm is disclosed in DE 10 2011 004 926 A1. The holding arm has a plurality of arm segments and a plurality of joints by means of which the separate arm segments are coupled to each other. The holding arm according to DE 10 2011 004 926 A1 also has a first interface at the proximal end, for coupling the holding arm to a standard rail on an operating table. The first interface is substantially in the form of a clamp. The holding arm also has an interface at the distal end, which is likewise in the form of a clamp and which is used to receive an endoscope. Even though this arm is basically well-suited for purely holding endoscopes, there is nevertheless a need to provide greater versatility in the range of uses for such holding arms, in particular to adapt them to different tasks. It is also desirable that the safety of such holding arms be improved such that the risk is reduced of a patient being injured during an operation in which the holding arm is used.
One disadvantage, however, is that precise positioning of the mechatronic assistance system and/or surgical instrument disposed on the holding arm is difficult to achieve with the holding arm known from the prior art, and is strongly dependent on the skill of the operator. The precision of positioning is confined solely to the skills of the operator who spatially positions the distal end of the arm.
One known way of eliminating this problem is to use robotically assisted holding arms which, in addition to releasable and lockable joints, also have motors in the joints, which can be controlled via a terminal. Precise positioning is possible with these robotically driven holding arms, but a robotic controller of this kind is highly complex and requires extensive training of the operator. Operating such a controller is complicated and may therefore cause problems.